1. Field of the Invention
The present invention relates to resilient, disposable ear plugs which fit inside the outer ear canal of a user. More specifically, the present invention relates to a resilient ear plug having a hygroscopic core which will absorb moisture from the ear canal of a user.
2. Description of the Prior Art
A large variety of ear plugs suited for various sound-protection and health purposes have been described in the patent literature. For instance, U.S. Pat. No. 2,538,339, issued Jan. 16, 1951, to M. J. Thomas, describes a conventional insert-type ear plug. The ear plug has a resilient main body portion surrounding a stiff inner core. The ear plug is designed to keep noise, dust, and water from entering the ear canal.
U.S. Pat. No. 2,824,558, issued Feb. 25, 1958, to P. L. Michael et al. (Canadian Patent No. 615,458, issued Feb. 28, 1961), describes an insert-type ear plug in which a hydraulic liquid is used to adjust the dimensions of the ear plug after it has been set in place within the ear of a user. The shape of the ear plug can also be altered by mechanical means. The ability to alter the surface configuration of the ear plug ensures a secure fit of the plug within the ear of a user.
U.S. Pat. No. 4,034,759, issued Jul. 12, 1977, to R. H. Haerr, describes a device which is essentially a cylindrical tube of compressed, dehydrated, cellular material. In its dehydrated state, the tube is sufficiently rigid to be inserted within the ear canal of a human user. The wick is then be hydrated with a liquid medicament. This causes the wick to expand radially outward to substantially fill the ear canal. Once hydrated, the wick will press firmly against the walls of the ear canal, while the hollow of the tube will allow sound waves to pass through the ear canal to the inner ear.
U.S. Pat. No. 2,253,452, issued Mar. 3, 1981, to W. R. Powers et al., describes an ear plug assembly including two open-cell, resilient foam plug bodies connected by a flexible cord. The resilient foam material from which the plug bodies are formed has a slow recovery rate. The cord is inserted into each of the plug bodies by inserting it into preformed holes in the plug bodies. The preformed holes then close about cord due to the recovery of the open-celled foam.
U.S. Pat. No. 4,774,938, issued Oct. 4, 1988, to H. S. Leight, describes a single ear plug similar to that of Powers, above. The Leight plug includes a bullet-shaped body made from a slow-recovery, open-cell, resilient material. Here, however, the plug body is molded from a urethane foam material in such a manner that the open cells at the surface of the plug body are much smaller that the cells within the mass of the plug body. The small surface cells limits the amount of dirt which is adhered to the plug by handling, compressing and inserting it into the ear canal of a user.
Similar compressible ear plugs are described in French Patent Nos. 1,215.869, issued Apr. 21, 1960; and 1,559,694, issued Mar. 14, 1969.
U.S. Pat. No. 5,195,539, issued Mar. 23, 1993, to J. F. Dyrud et al., describes a device for compressing slow recovery earplugs prior to insertion into the ear canal of a user.